3/5/2012. Study Questions. Global Warming. Weather: daily temperature and moisture conditions Climate: long-term weather patterns

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1 Study Questions Global Warming 1. Explain what is meant by the term Greenhouse effect. 2. List 3 indications that global climate is currently increasing. 3. Describe 3 possible consequences of global warming. 4. Name 3 greenhouse gases and explain where they come from. 5. Discuss ways to reduce the production of greenhouse gases. 6. Why do you think this is a controversial topic? Weather: daily temperature and moisture conditions Climate: long-term weather patterns Troposphere: air directly above earth s surface, extending up to 5-10 miles from earth s surface Stratosphere: ozone-rich layer above troposphere, extending up to 30 miles above earth s surface Energy from the sun reaches earth s atmosphere: 25% is reflected, another 25% is absorbed 50% reaches earth s surface (as light or near-infrared energy) and is either reflected or absorbed Albedo: reflectivity, how much light is reflected by a substance Energy that is absorbed will eventually be re-emitted as longer wavelength infrared energy (heat) This reemitted energy heats up the atmosphere Greenhouse effect: atmosphere transmits light from sun, which is converted to heat, only some of which the atmosphere transmits; remaining heat becomes trapped Note: this is a natural process essential for life John Tyndall Svante Arrhenius commons.wikimedia.org/wiki/file:john_tyndall_

2 Important Questions about Global Warming Are global temperatures increasing? Is this a problem? Are human activities contributing to these changes? What, if anything, do we need to do about this? Greenhouse gases include: Carbon dioxide (CO 2 ) Methane (CH 4 ) Chlorofluorocarbons (CFCs) Nitrous oxide (N 2 O) Climate History Climate is highly variable Climate change can occur gradually or abruptly Climate is related to CO 2 atmospheric concentration Current Evidence of Global Warming: Increased global temperatures Shrinking and thinning arctic and Antarctic ice packs Retreating glaciers Decline and changes in wildlife patterns Damaged and declining coral reefs Rising sea level Longer growing seasons Increased frequency of droughts Increased severity of storms Increased global temperatures Average temperature has increased 0.6 o C over the last 100 years Some places have increased by as much as 4 o C over the last 50 years! 19/20 of the hottest years in the past 150 have occurred since 1980 picasaweb.google.com/.../0qbjaoy4awgye6dblkufha 2

3 Thinning and Shrinking Ice in the Arctic Greenland s Ice Cap Shrinking and thinning Ice in the Antarctic Retreating Glaciers Alaska, 1906 Alaska, 2004 Decline and changes in wildlife patterns

4 Damaged and declining coral reefs Rising sea level Longer growing seasons Increased precipitation and storms Consequences of Global Warming Flooding/rising sea levels Flooding/rising sea levels Damage to ecosystems Fresh-water resources Human health issues Increased coastal flooding Decreased mangroves, salt marshes 4

5 Past Damage to ecosystems Tundra, coniferous forests, coral reefs, mangroves, salt marshes, sea ice biomes especially vulnerable Projected Decrease in biodiversity Habitat degradation, loss Extinction Acidification of oceans Freshwater resources Decreased water supply Decreased sustainable development Less freshwater in groundwater and estuaries Increased population at risk of flooding in river basins Human health Increased heat-related deaths Increased risk of flooding Hunger, malnutrtition Increased spread of disease Increased ozone-related deaths Human Contributions to Global Warming? Burning fossil fuels CO 2 Greenhouse gases include: carbon dioxide (CO 2 ) methane (CH 4 ) nitrous oxide (N 2 O) Where do these gases come from? Removing forests and grasslands CO 2 and N 2 O Cultivating rice paddies, inorganic fertilizers N2O Raising cattle CH 4 5

6 What s Being Done? Intergovernmental Panel on Climate Change (IPCC) (established in 1988) 1992 Earth Summit meeting in Rio de Janeiro created agreement to reduce CO 2 emissions was signed by many nations 1997 Kyoto Protocol treaty, agreeing to reduce greenhouse gas emissions by 5% of 1990 levels by 2012, was signed by 160 nations Controlling greenhouse gas emissions is the key: Use natural gas instead of coal Promote energy efficient appliances Use renewable energy sources Plant trees Store excess CO 2 Capture and use excess CH 4 Reduce bovine flatulence! Geoenginerering Important Questions about Global Warming Are global temperatures increasing? Is this a problem? Are human activities contributing to these changes? What, if anything, do we need to do about this? 6